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Thompson JS, Bixler SA, Qian F, Vora K, Scott ML, Cachero TG, Hession C, Schneider P, Sizing ID, Mullen C, Strauch K, Zafari M, Benjamin CD, Tschopp J, Browning JL, Ambrose C. BAFF-R, a newly identified TNF receptor that specifically interacts with BAFF. Science 2001; 293:2108-11. [PMID: 11509692 DOI: 10.1126/science.1061965] [Citation(s) in RCA: 705] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
B cell homeostasis has been shown to critically depend on BAFF, the B cell activation factor from the tumor necrosis factor (TNF) family. Although BAFF is already known to bind two receptors, BCMA and TACI, we have identified a third receptor for BAFF that we have termed BAFF-R. BAFF-R binding appears to be highly specific for BAFF, suggesting a unique role for this ligand-receptor interaction. Consistent with this, the BAFF-R locus is disrupted in A/WySnJ mice, which display a B cell phenotype qualitatively similar to that of the BAFF-deficient mice. Thus, BAFF-R appears to be the principal receptor for BAFF-mediated mature B cell survival.
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MESH Headings
- Amino Acid Sequence
- Animals
- B-Cell Activating Factor
- B-Cell Activation Factor Receptor
- B-Cell Maturation Antigen
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- B-Lymphocytes/physiology
- Cell Line
- Chromosome Mapping
- Chromosomes, Human, Pair 22
- Cloning, Molecular
- Homeostasis
- Humans
- Ligands
- Lymphoid Tissue/metabolism
- Male
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred A
- Mice, Inbred C57BL
- Molecular Sequence Data
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Tumor Necrosis Factor/chemistry
- Receptors, Tumor Necrosis Factor/genetics
- Receptors, Tumor Necrosis Factor/metabolism
- Recombinant Fusion Proteins/metabolism
- Signal Transduction
- Transfection
- Transmembrane Activator and CAML Interactor Protein
- Tumor Necrosis Factor-alpha/metabolism
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705 |
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Hanaoka K, Qian F, Boletta A, Bhunia AK, Piontek K, Tsiokas L, Sukhatme VP, Guggino WB, Germino GG. Co-assembly of polycystin-1 and -2 produces unique cation-permeable currents. Nature 2000; 408:990-4. [PMID: 11140688 DOI: 10.1038/35050128] [Citation(s) in RCA: 637] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The human kidney is composed of roughly 1.2-million renal tubules that must maintain their tubular structure to function properly. In autosomal dominant polycystic kidney disease (ADPKD) cysts develop from renal tubules and enlarge independently, in a process that ultimately causes renal failure in 50% of affected individuals. Mutations in either PKD1 or PKD2 are associated with ADPKD but the function of these genes is unknown. PKD1 is thought to encode a membrane protein, polycystin-1, involved in cell-cell or cell-matrix interactions, whereas the PKD2 gene product, polycystin-2, is thought to be a channel protein. Here we show that polycystin-1 and -2 interact to produce new calcium-permeable non-selective cation currents. Neither polycystin-1 nor -2 alone is capable of producing currents. Moreover, disease-associated mutant forms of either polycystin protein that are incapable of heterodimerization do not result in new channel activity. We also show that polycystin-2 is localized in the cell in the absence of polycystin-1, but is translocated to the plasma membrane in its presence. Thus, polycystin-1 and -2 co-assemble at the plasma membrane to produce a new channel and to regulate renal tubular morphology and function.
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Batten M, Groom J, Cachero TG, Qian F, Schneider P, Tschopp J, Browning JL, Mackay F. BAFF mediates survival of peripheral immature B lymphocytes. J Exp Med 2000; 192:1453-66. [PMID: 11085747 PMCID: PMC2193190 DOI: 10.1084/jem.192.10.1453] [Citation(s) in RCA: 554] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
B cell maturation is a very selective process that requires finely tuned differentiation and survival signals. B cell activation factor from the TNF family (BAFF) is a TNF family member that binds to B cells and potentiates B cell receptor (BCR)-mediated proliferation. A role for BAFF in B cell survival was suggested by the observation of reduced peripheral B cell numbers in mice treated with reagents blocking BAFF, and high Bcl-2 levels detected in B cells from BAFF transgenic (Tg) mice. We tested in vitro the survival effect of BAFF on lymphocytes derived from primary and secondary lymphoid organs. BAFF induced survival of a subset of splenic immature B cells, referred to as transitional type 2 (T2) B cells. BAFF treatment allowed T2 B cells to survive and differentiate into mature B cells in response to signals through the BCR. The T2 and the marginal zone (MZ) B cell compartments were particularly enlarged in BAFF Tg mice. Immature transitional B cells are targets for negative selection, a feature thought to promote self-tolerance. These findings support a model in which excessive BAFF-mediated survival of peripheral immature B cells contributes to the emergence and maturation of autoreactive B cells, skewed towards the MZ compartment. This work provides new clues on mechanisms regulating B cell maturation and tolerance.
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Qian F, Germino FJ, Cai Y, Zhang X, Somlo S, Germino GG. PKD1 interacts with PKD2 through a probable coiled-coil domain. Nat Genet 1997; 16:179-83. [PMID: 9171830 DOI: 10.1038/ng0697-179] [Citation(s) in RCA: 498] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) describes a group of at least three genetically distinct disorders with almost identical clinical features that collectively affects 1:1,000 of the population. Affected individuals typically develop large cystic kidneys and approximately one half develop end-stage renal disease by their seventh decade. It has been suggested that the diseases result from defects in interactive factors involved in a common pathway. The recent discovery of the genes for the two most common forms of ADPKD has provided an opportunity to test this hypothesis. We describe a previously unrecognized coiled-coil domain within the C terminus of the PKD1 gene product, polycystin, and demonstrate that it binds specifically to the C terminus of PKD2. Homotypic interactions involving the C terminus of each are also demonstrated. We show that naturally occurring pathogenic mutations of PKD1 and PKD2 disrupt their associations. We have characterized the structural basis of their heterotypic interactions by deletional and site-specific mutagenesis. Our data suggest that PKD1 and PKD2 associate physically in vivo and may be partners of a common signalling cascade involved in tubular morphogenesis.
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Qian F, Watnick TJ, Onuchic LF, Germino GG. The molecular basis of focal cyst formation in human autosomal dominant polycystic kidney disease type I. Cell 1996; 87:979-87. [PMID: 8978603 DOI: 10.1016/s0092-8674(00)81793-6] [Citation(s) in RCA: 417] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a common disease and an important cause of renal failure. It is characterized by considerable intrafamilial phenotypic variation and focal cyst formation. To elucidate the molecular basis for these observations, we have developed a novel method for isolating renal cystic epithelia from single cysts and have used it to show that individual renal cysts in ADPKD are monoclonal. Loss of heterozygosity was discovered within a subset of cysts for two closely linked polymorphic markers located within the PKD1 gene. Genetic analysis revealed that it was the normal haplotype that was lost. This study provides a molecular explanation for the focal nature of cyst formation and a probable mechanism whereby mutations cause disease. The high rate at which "second hits" must occur to account for the large number of cysts observed suggests that unique structural features of the PKD1 gene may be responsible for its mutability.
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Boletta A, Qian F, Onuchic LF, Bhunia AK, Phakdeekitcharoen B, Hanaoka K, Guggino W, Monaco L, Germino GG. Polycystin-1, the gene product of PKD1, induces resistance to apoptosis and spontaneous tubulogenesis in MDCK cells. Mol Cell 2000; 6:1267-73. [PMID: 11106764 DOI: 10.1016/s1097-2765(00)00123-4] [Citation(s) in RCA: 169] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The major form of autosomal dominant polycystic kidney disease (ADPKD) results from mutation of a gene (PKD1) of unknown function that is essential for the later stages of renal tubular differentiation. In this report, we describe a novel cell culture system for studying how PKD1 regulates this process. We show that expression of human PKD1 in MDCK cells slows their growth and protects them from programmed cell death. MDCK cells expressing PKD1 also spontaneously form branching tubules while control cells form simple cysts. Increased cell proliferation and apoptosis have been implicated in the pathogenesis of cystic diseases. Our study suggests that PKD1 may function to regulate both pathways, allowing cells to enter a differentiation pathway that results in tubule formation.
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169 |
7
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Qian F, Vaux DL, Weissman IL. Expression of the integrin alpha 4 beta 1 on melanoma cells can inhibit the invasive stage of metastasis formation. Cell 1994; 77:335-47. [PMID: 8181055 DOI: 10.1016/0092-8674(94)90149-x] [Citation(s) in RCA: 155] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Among a series of adhesion molecules, expression of integrin alpha 4 beta 1 showed a unique inverse correlation with the invasive potential of B16 melanoma cell lines. When an alpha 4 cDNA was introduced into an alpha 4-beta 1+ highly invasive melanoma line, alpha 4 beta 1 heterodimers were expressed on the surface. Matrigel invasion by the alpha 4+ beta 1+ cells was reduced. Pulmonary metastasis was also suppressed when the transfectants were placed subcutaneously, but not when injected intravenously. Expression of alpha 4 beta 1 promoted homotypic intercellular adhesion. The homotypic adhesion was abrogated, and the alpha 4+ beta 1+ (less invasive cell lines) increased matrigel invasion following the anti-alpha 4 MAb treatment. These results suggest that integrin alpha 4 beta 1 could play a role in controlling melanoma cell metastasis at the invasive stage.
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MESH Headings
- Animals
- Antibodies, Monoclonal
- Cell Adhesion/physiology
- Cell Adhesion Molecules/analysis
- Collagen
- DNA, Complementary
- Drug Combinations
- Genetic Vectors
- Integrin alpha4beta1
- Integrins/analysis
- Integrins/biosynthesis
- Integrins/genetics
- Laminin
- Lung Neoplasms/secondary
- Male
- Melanoma, Experimental/metabolism
- Melanoma, Experimental/pathology
- Melanoma, Experimental/secondary
- Mice
- Mice, Inbred C57BL
- Neoplasm Invasiveness
- Proteoglycans
- RNA, Messenger/analysis
- RNA, Messenger/biosynthesis
- Receptors, Very Late Antigen/analysis
- Receptors, Very Late Antigen/biosynthesis
- Receptors, Very Late Antigen/genetics
- Retroviridae/genetics
- Tumor Cells, Cultured
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Ibraghimov-Beskrovnaya O, Dackowski WR, Foggensteiner L, Coleman N, Thiru S, Petry LR, Burn TC, Connors TD, Van Raay T, Bradley J, Qian F, Onuchic LF, Watnick TJ, Piontek K, Hakim RM, Landes GM, Germino GG, Sandford R, Klinger KW. Polycystin: in vitro synthesis, in vivo tissue expression, and subcellular localization identifies a large membrane-associated protein. Proc Natl Acad Sci U S A 1997; 94:6397-402. [PMID: 9177229 PMCID: PMC21061 DOI: 10.1073/pnas.94.12.6397] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/1997] [Accepted: 04/11/1997] [Indexed: 02/04/2023] Open
Abstract
The primary structure of polycystin predicts a large integral membrane protein with multiple cell recognition motifs, but its function remains unknown. Insight into polycystin's normal function and its role in the development of autosomal dominant polycystic kidney disease (PKD1) requires the assembly of an extensive collection of molecular reagents to examine its expression and create model systems for functional studies. Development of these crucial reagents has been complicated due to the presence of transcriptionally active homologous loci. We have assembled the authentic full-length PKD1 cDNA and demonstrated expression of polycystin in vitro. Polyclonal antibodies directed against distinct extra- and intracellular domains specifically immunoprecipitated in vitro translated polycystin. The panel of antibodies was used to determine localization of polycystin in renal epithelial and endothelial cell lines and tissues of fetal, adult, and cystic origins. In normal adult kidney and maturing fetal nephrons, polycystin expression was confined to epithelial cells of the distal nephron and vascular endothelial cells. Expression in the proximal nephron was only observed after injury-induced cell proliferation. Polycystin expression was confined to ductal epithelium in liver, pancreas, and breast, and restricted to astrocytes in normal brain. We report clear evidence for the membrane localization of polycystin by both tissue sections and by confocal microscopy in cultured renal and endothelial cells. Interestingly, when cultured cells made cell-cell contact, polycystin was localized to the lateral membranes of cells in contact. These data suggest that polycystin is likely to have a widespread role in epithelial cell differentiation and maturation and in cell-cell interactions.
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Watnick TJ, Torres VE, Gandolph MA, Qian F, Onuchic LF, Klinger KW, Landes G, Germino GG. Somatic mutation in individual liver cysts supports a two-hit model of cystogenesis in autosomal dominant polycystic kidney disease. Mol Cell 1998; 2:247-51. [PMID: 9734362 DOI: 10.1016/s1097-2765(00)80135-5] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD), Type I is a common genetic disorder and an important cause of renal failure. The disease is characterized by progressive cyst formation in a variety of organs including the kidney, liver and pancreas. We have previously shown that in the case of PKD1, renal cyst development is likely to require somatic inactivation of the normal allele coupled to a germline PKD1 mutation. In this report, we have used unique reagents to show that intragenic, somatic mutations are common in hepatic cysts. All pathogenic mutations were shown to have altered the previously normal copy of the gene. These data extend the "two-hit" model of cystogenesis to include a second focal manifestation of the disease.
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Zheng C, Yang Q, Cao J, Xie N, Liu K, Shou P, Qian F, Wang Y, Shi Y. Local proliferation initiates macrophage accumulation in adipose tissue during obesity. Cell Death Dis 2016; 7:e2167. [PMID: 27031964 PMCID: PMC4823955 DOI: 10.1038/cddis.2016.54] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 01/31/2016] [Accepted: 02/15/2016] [Indexed: 12/18/2022]
Abstract
Obesity-associated chronic inflammation is characterized by an accumulation of adipose tissue macrophages (ATMs). It is generally believed that those macrophages are derived from peripheral blood monocytes. However, recent studies suggest that local proliferation of macrophages is responsible for ATM accumulation. In the present study, we revealed that both migration and proliferation contribute to ATM accumulation during obesity development. We show that there is a significant increase in ATMs at the early stage of obesity, which is largely due to an enhanced in situ macrophage proliferation. This result was obtained by employing fat-shielded irradiation and bone marrow reconstitution. Additionally, the production of CCL2, a pivotal chemoattractant of monocytes, was not found to be increased at this stage, corroborating with a critical role of proliferation. Nonetheless, as obesity proceeds, the role of monocyte migration into adipose tissue becomes more significant and those new immigrants further proliferate locally. These proliferating ATMs mainly reside in crown-like structures formed by macrophages surrounding dead adipocytes. We further showed that IL-4/STAT6 is a driving force for ATM proliferation. Therefore, we demonstrated that local proliferation of resident macrophages contributes to ATM accumulation during obesity development and has a key role in obesity-associated inflammation.
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Research Support, Non-U.S. Gov't |
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125 |
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Guo R, Zhang S, Xiao M, Qian F, He Z, Li D, Zhang X, Li H, Yang X, Wang M, Chai R, Tang M. Accelerating bioelectric functional development of neural stem cells by graphene coupling: Implications for neural interfacing with conductive materials. Biomaterials 2016; 106:193-204. [PMID: 27566868 DOI: 10.1016/j.biomaterials.2016.08.019] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/08/2016] [Accepted: 08/13/2016] [Indexed: 12/17/2022]
Abstract
In order to govern cell-specific behaviors in tissue engineering for neural repair and regeneration, a better understanding of material-cell interactions, especially the bioelectric functions, is extremely important. Graphene has been reported to be a potential candidate for use as a scaffold and neural interfacing material. However, the bioelectric evolvement of cell membranes on these conductive graphene substrates remains largely uninvestigated. In this study, we used a neural stem cell (NSC) model to explore the possible changes in membrane bioelectric properties - including resting membrane potentials and action potentials - and cell behaviors on graphene films under both proliferation and differentiation conditions. We used a combination of single-cell electrophysiological recordings and traditional cell biology techniques. Graphene did not affect the basic membrane electrical parameters (capacitance and input resistance), but resting membrane potentials of cells on graphene substrates were more strongly negative under both proliferation and differentiation conditions. Also, NSCs and their progeny on graphene substrates exhibited increased firing of action potentials during development compared to controls. However, graphene only slightly affected the electric characterizations of mature NSC progeny. The modulation of passive and active bioelectric properties on the graphene substrate was accompanied by enhanced NSC differentiation. Furthermore, spine density, synapse proteins expressions and synaptic activity were all increased in graphene group. Modeling of the electric field on conductive graphene substrates suggests that the electric field produced by the electronegative cell membrane is much higher on graphene substrates than that on control, and this might explain the observed changes of bioelectric development by graphene coupling. Our results indicate that graphene is able to accelerate NSC maturation during development, especially with regard to bioelectric evolvement. Our findings provide a fundamental understanding of the role of conductive materials in tuning the membrane bioelectric properties in a graphene model and pave the way for future studies on the development of methods and materials for manipulating membrane properties in a controllable way for NSC-based therapies.
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Research Support, Non-U.S. Gov't |
9 |
105 |
12
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Singh RK, Qian F, Nagabushnam V, Damodaran R, Moudgil BM. Excimer laser deposition of hydroxyapatite thin films. Biomaterials 1994; 15:522-8. [PMID: 7918905 DOI: 10.1016/0142-9612(94)90018-3] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have demonstrated a new and simple in situ method to fabricate adherent and dense hydroxyapatite (HA) coatings at relatively low deposition temperatures (500-600 degrees C). Under optimum processing conditions, the HA coatings possess a nominal Ca:P ratio of 1.65 and exhibit a fully crystalline single-phase structure. This deposition technique is based on the application of a pulsed excimer laser (wavelength lambda = 248 nm, pulse duration tau = 25 x 10(-9) s) to ablate a dense stoichiometric HA target. The HA target was prepared by standard ceramic coprecipitation techniques followed by cold pressing and further sintering at 1200 degrees C in air. High substrate temperatures (> or = 600 degrees C) during film deposition led to phosphorus deficient coatings because of re-evaporation of phosphorus during the deposition process. The stabilization of various calcium and phosphorus phases in the film was controlled by a number of process parameters such as substrate temperature, chamber pressure and presence of water vapour in the chamber. This is particularly advantageous for production of HA coatings, since it is known that HA decomposes at high temperatures due to the uncertainty in the starting material stoichiometry. Rutherford backscattering spectrometry, energy dispersive X-ray analysis, transmission electron microscopy, scanning electron microscopy and X-ray diffraction techniques were employed to determine the structure-processing relationships. Qualitative scratch measurements were conducted to determine the adhesion strength of the films.
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Dexter F, Macario A, Qian F, Traub RD. Forecasting surgical groups' total hours of elective cases for allocation of block time: application of time series analysis to operating room management. Anesthesiology 1999; 91:1501-8. [PMID: 10551603 DOI: 10.1097/00000542-199911000-00044] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Allocation of the correct amount of operating room (OR) "block time" can provide surgeons with access to sufficient OR time to complete their elective cases while optimally matching staffing with the elective case workload (to maximize labor productivity). To evaluate how to predict accurately total hours of elective cases performed by a surgical group using data from surgical services information systems, the authors addressed the following questions: (1) How many previous 4-week periods of data should be used to minimize error in forecasting a surgical group's total hours of elective cases? (2) Using the number of 4-week periods from question #1, can we detect trends or correlations between successive periods that could be used to improve forecasting accuracy? (3) How can results from questions #1 and #2 be used to calculate an upper prediction bound (upper limit) for the total hours of elective cases that will be completed in a future period? Prediction bounds can be used to budget staffing accurately. METHODS Time series analysis was performed on total hours of elective cases over 39 consecutive 4-week periods from 17 surgical groups. RESULTS The average of 12 consecutive periods' total hours of elective cases had an appropriate error profile. The observations within each series of 12 consecutive 4-week periods followed a normal distribution, with each observation of total hours of elective cases not correlated with the subsequent observation. CONCLUSIONS The average of the most recent 12 4-week periods can be used to predict surgical groups' future use of block time.
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14
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Roe MW, Worley JF, Qian F, Tamarina N, Mittal AA, Dralyuk F, Blair NT, Mertz RJ, Philipson LH, Dukes ID. Characterization of a Ca2+ release-activated nonselective cation current regulating membrane potential and [Ca2+]i oscillations in transgenically derived beta-cells. J Biol Chem 1998; 273:10402-10. [PMID: 9553098 DOI: 10.1074/jbc.273.17.10402] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Although stimulation of insulin secretion by glucose is regulated by coupled oscillations of membrane potential and intracellular Ca2+ ([Ca2+]i), the membrane events regulating these oscillations are incompletely understood. In the presence of glucose and tetraethylammonium, transgenically derived beta-cells (betaTC3-neo) exhibit coupled voltage and [Ca2+]i oscillations strikingly similar to those observed in normal islets in response to glucose. Using these cells as a model system, we investigated the membrane conductance underlying these oscillations. Alterations in delayed rectifier or Ca2+-activated K+ channels were excluded as a source of the conductance oscillations, as they are completely blocked by tetraethylammonium. ATP-sensitive K+ channels were also excluded, since the ATP-sensitive K+ channel blocker tolbutamide substituted for glucose in inducing [Ca2+]i oscillations. Thapsigargin, which depletes intracellular Ca2+ stores, and maitotoxin, an activator of nonselective cation channels, both converted the glucose-dependent [Ca2+]i oscillations into a sustained elevation. On the other hand, both SKF 96365, a blocker of Ca2+ store-operated channels, and external Na+ removal suppressed the glucose-stimulated [Ca2+]i oscillations. Maitotoxin activated a nonselective cation current in betaTC3 cells that was attenuated by removal of extracellular Na+ and by SKF 96365, in the same manner to a current activated in mouse beta-cells following depletion of intracellular Ca2+ stores. Currents similar to these are produced by the mammalian trp-related channels, a gene family that includes Ca2+ store-operated channels and inositol 1,4,5-trisphosphate-activated channels. We found several of the trp family genes were expressed in betaTC3 cells by reverse transcriptase polymerase chain reaction using specific primers, but by Northern blot analysis, mtrp-4 was the predominant message expressed. We conclude that a conductance underlying glucose-stimulated oscillations in beta-cells is provided by a Ca2+ store depletion-activated nonselective cation current, which is plausibly encoded by homologs of trp genes.
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Reynolds DM, Hayashi T, Cai Y, Veldhuisen B, Watnick TJ, Lens XM, Mochizuki T, Qian F, Maeda Y, Li L, Fossdal R, Coto E, Wu G, Breuning MH, Germino GG, Peters DJ, Somlo S. Aberrant splicing in the PKD2 gene as a cause of polycystic kidney disease. J Am Soc Nephrol 1999; 10:2342-51. [PMID: 10541293 DOI: 10.1681/asn.v10112342] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
It is estimated that approximately 15% of families with autosomal dominant polycystic kidney disease (ADPKD) have mutations in PKD2. Identification of these mutations is central to identifying functionally important regions of gene and to understanding the mechanisms underlying the pathogenesis of the disorder. The current study describes mutations in six type 2 ADPKD families. Two single base substitution mutations discovered in the ORF in exon 14 constitute the most COOH-terminal pathogenic variants described to date. One of these mutations is a nonsense change and the other encodes an apparent missense variant. Reverse transcription-PCR from patient lymphoblast RNA showed that, in addition, both mutations resulted in out-of-frame splice variants by activating cryptic splice sites via different mechanisms. The apparent missense variant produced such a strong splicing signal that the processed transcript from the mutant chromosome did not contain any of the normally spliced, missense product. A third mutation, a nonconservative missense change effecting a negatively charged residue in the third transmembrane span, is likely pathogenic and defines a highly conserved residue consistent with a potential channel subunit function for polycystin-2. The remaining three mutations included two frame shifts resulting from deletion of one or two bases in exons 6 and 10, respectively, and a nonsense mutation due to a single base substitution in exon 4. The study also defined a novel intragenic polymorphism in exon 1 that will be useful in analyzing "second hits" in PKD2. Finally, the study demonstrates that there are reduced levels of normal polycystin-2 protein in lymphoblast lines from PKD2-affected individuals and that truncated mutant polycystin-2 cannot be detected in patient lymphoblasts, suggesting that the latter may be unstable in at least some tissues. The mutations described will serve as critical reagents for future functional studies in PKD2.
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Watnick TJ, Piontek KB, Cordal TM, Weber H, Gandolph MA, Qian F, Lens XM, Neumann HP, Germino GG. An unusual pattern of mutation in the duplicated portion of PKD1 is revealed by use of a novel strategy for mutation detection. Hum Mol Genet 1997; 6:1473-81. [PMID: 9285784 DOI: 10.1093/hmg/6.9.1473] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The gene for the most common and severe form of autosomal dominant polycystic kidney disease, PKD1, encodes a 14 kb mRNA that is predicted to result in an integral membrane protein of 4302 amino acids. The major challenge faced by researchers attempting to complete mutation analysis of the PKD1 gene has been the presence of several homologous loci also located on chromosome 16. Because the sequence of PKD1 and its homologs is nearly identical in the 5' region of the gene, most traditional approaches to mutation analysis cannot distinguish sequence variants occurring uniquely in PKD1. Therefore, only a small number of mutations have been identified to date and these have all been found in the 3', unique portion of the gene. In order to begin analysis of the duplicated region of PKD1, we have devised a novel strategy that depends on long-range PCR and a single gene-specific primer from the unique region of the gene to amplify a PKD1-specific template that spans exons 23-34. This 10 kb template, amplified from genomic DNA, can be employed for mutation analysis using a wide variety of sequence-based approaches. We have used our long-range PCR strategy to begin screening for sequence variants with heteroduplex analysis, and several affected individuals were discovered to have clusters of base pair substitutions in exons 23 and 25. In two patients, these changes, identified in exon 23, would be predicted to result in multiple amino acid substitutions in a short stretch of the protein. This clustering of base pair substitutions is unusual and suggests that mutation may result from unique structural features of the PKD1 gene.
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Kruse U, Qian F, Sippel AE. Identification of a fourth nuclear factor I gene in chicken by cDNA cloning: NFI-X. Nucleic Acids Res 1991; 19:6641. [PMID: 1754401 PMCID: PMC329238 DOI: 10.1093/nar/19.23.6641] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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He F, Zhang S, Qian F, Zhang C. Delayed dystonia with striatal CT lucencies induced by a mycotoxin (3-nitropropionic acid). Neurology 1995; 45:2178-83. [PMID: 8848189 DOI: 10.1212/wnl.45.12.2178] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We describe a clinical syndrome of delayed dystonia in children subsequent to initial gastrointestinal symptoms and acute noninflammatory encephalopathy. The syndrome was caused by the ingestion of mildewed sugarcane containing the Arthrinium-produced mycotoxin, 3-nitropropionic acid (3-NPA). In the severely affected patients, intoxication usually was heralded by coma, with dystonia appearing 7 to 40 days after recovery from the coma. The dystonia was manifested as choreoathetosis, torsion spasms, or painful paroxysmal spasms of the extremities and was neither progressive nor reversible. CTs of the dystonic patients consistently showed bilateral hypodensities in the lenticular nuclei. The pathogenesis of the selective lenticular lesions induced by 3-NPA is not yet clear.
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Qian F, Kruse U, Lichter P, Sippel AE. Chromosomal localization of the four genes (NFIA, B, C, and X) for the human transcription factor nuclear factor I by FISH. Genomics 1995; 28:66-73. [PMID: 7590749 DOI: 10.1006/geno.1995.1107] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Nuclear Factor I (NFI) proteins constitute a family of dimeric DNA-binding proteins with very similar, possibly identical, DNA-binding specificity. They function as cellular transcription factors and as replication factors for adenovirus DNA replication. Diversity in this protein family is generated by multiple genes, differential splicing, and heterodimerization. To determine the chromosomal position of NFI genes in the human genome, we isolated partial cDNA sequences derived from four independent genes: NFIA, NFIB, NFIC, and NFIX. Corresponding clones of genomic DNA served as probes for fluorescence in situ hybridization on human metaphase chromosomes. The NFIA and NFIB genes map to positions 1p31.2-p31.3 and 9p24.1, respectively. The NFIC and the NFIX genes were both localized to position 19p13.3 in the order centromere-NFIX-NFIC-telomere. Comparison of the position of NFI genes and JUN genes revealed a close physical linkage between members of the NFI and JUN gene families in the human genome.
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Joun H, Lanske B, Karperien M, Qian F, Defize L, Abou-Samra A. Tissue-specific transcription start sites and alternative splicing of the parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor gene: a new PTH/PTHrP receptor splice variant that lacks the signal peptide. Endocrinology 1997; 138:1742-9. [PMID: 9075739 DOI: 10.1210/endo.138.4.5085] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The PTH/PTHrP receptor gene is expressed in bone and kidney as well as in many other tissues. Using primer extension followed by rapid cloning of amplified complementary DNA ends, we have isolated new PTH/PTHrP receptor complementary DNAs with different splicing patterns and have characterized a new upstream transcription start site. Three 5' nontranslated exons, U3, U2 and U1, located 4.8, 2.5, and 1.2 kb upstream of the exon that encodes the putative signal peptide of the classical receptor (exon S), have been characterized. Four types of splicing patterns were recognized. Type I splicing pattern is transcribed from exon U1 and is spliced to exons S and E1; this pattern was found in most tissues tested. Types II, III, and IV splicing patterns are transcribed from exon U3 and have a restricted tissue distribution. Type II splice pattern, containing exons U3, U2, and S and type III splicing pattern, containing exon U3, U2, and E1 (skipping exon S), was found only in kidney. Type IV splice pattern, containing exon U3 and S was found both in kidney and ovary. Because the type III splice variant skips exon S, translation of this splice variant initiates at a different AUG codon. The type III splice variant was weakly expressed on the cell surface of COS-7 cells, as assessed by double antibody binding assay, and no detectable ligand binding was observed on intact cells. The type III splice variant, however, increased cAMP accumulation in COS-7 cells when challenged with PTH(1-34), PTH(1-84) and hPTHrP(1-36) with EC50s that are similar to those observed in COS-7 cells expressing the type I variant but with a maximum stimulation that was lower than that observed in COS-7 cells expressing the type I variant. These data indicate low levels of cell surface expression of the type III splice variant. Treatment of COS-7 cells with tunicamycin decreased the size of the type I splice variant from a broad band of 85 kDa to a compact band of about 60 kDa. The type III splice variant did not change in size in COS-7 cells treated with tunicamycin, indicating that the type III splice variant did not undergo any glycosylation step. In conclusion, the PTH/PTHrP receptor gene uses alternate promoters in a tissue-specific manner that results in several tissue-specific alternatively spliced transcripts. One of these transcripts, the type III splice variant, is expressed in kidney and lacks the signal peptide.
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Lv YB, Yin ZX, Chei CL, Brasher MS, Zhang J, Kraus VB, Qian F, Shi XM, Matchar DB, Zeng Y. Serum cholesterol levels within the high normal range are associated with better cognitive performance among Chinese elderly. J Nutr Health Aging 2016; 20:280-7. [PMID: 26892577 DOI: 10.1007/s12603-016-0701-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Qian F, Hanahan D, Weissman IL. L-selectin can facilitate metastasis to lymph nodes in a transgenic mouse model of carcinogenesis. Proc Natl Acad Sci U S A 2001; 98:3976-81. [PMID: 11274419 PMCID: PMC31164 DOI: 10.1073/pnas.061633698] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2000] [Indexed: 11/18/2022] Open
Abstract
L-selectin mediates homing of lymphocytes to lymph nodes (LN). Transgenic mice that express rat insulin promoter regulated simian virus 40 Tag (RIP-Tag) develop large, local cancers that metastasize to liver but not LN. To test whether this lack of LN metastases reflects their absence from the circulation, transgenic mice were produced that express Tag (T), L-selectin (L), and Escherichia coli LacZ (Z), in pancreatic beta cells. LTZ mice developed insulinomas that specifically had LN metastases; metastasis was blocked by an anti L-selectin mAb. LacZ(+) tumor cells from these LN homed to secondary LN upon transfer. These results suggest that the highly vascularized islet carcinomas are shedding tumor cells into the bloodstream, which is a necessary but insufficient condition for metastasis to occur; L-selectin can facilitate homing of such tumor cells to LN, resulting in metastasis.
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Yu X, Liu W, Fan Z, Qian F, Zhang D, Han Y, Xu L, Sun G, Qi J, Zhang S, Tang M, Li J, Chai R, Wang H. c-Myb knockdown increases the neomycin-induced damage to hair-cell-like HEI-OC1 cells in vitro. Sci Rep 2017; 7:41094. [PMID: 28112219 PMCID: PMC5253735 DOI: 10.1038/srep41094] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 12/14/2016] [Indexed: 12/17/2022] Open
Abstract
c-Myb is a transcription factor that plays a key role in cell proliferation, differentiation, and apoptosis. It has been reported that c-Myb is expressed within the chicken otic placode, but whether c-Myb exists in the mammalian cochlea, and how it exerts its effects, has not been explored yet. Here, we investigated the expression of c-Myb in the postnatal mouse cochlea and HEI-OC1 cells and found that c-Myb was expressed in the hair cells (HCs) of mouse cochlea as well as in cultured HEI-OC1 cells. Next, we demonstrated that c-Myb expression was decreased in response to neomycin treatment in both cochlear HCs and HEI-OC1 cells, suggesting an otoprotective role for c-Myb. We then knocked down c-Myb expression with shRNA transfection in HEI-OC1 cells and found that c-Myb knockdown decreased cell viability, increased expression of pro-apoptotic factors, and enhanced cell apoptosis after neomycin insult. Mechanistic studies revealed that c-Myb knockdown increased cellular levels of reactive oxygen species and decreased Bcl-2 expression, both of which are likely to be responsible for the increased sensitivity of c-Myb knockdown cells to neomycin. This study provides evidence that c-Myb might serve as a new target for the prevention of aminoglycoside-induced HC loss.
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Pulido MT, Wefel JS, Hernandez MM, Denehy GE, Guzman-Armstrong S, Chalmers JM, Qian F. The Inhibitory Effect of MI Paste, Fluoride and a Combination of Both on the Progression of Artificial Caries-like Lesions in Enamel. Oper Dent 2008; 33:550-5. [DOI: 10.2341/07-136] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Clinical Relevance
It is important to evaluate the inhibitory effect on lesion progression of CPP-ACP when delivered in a mousse vehicle, commercially known as MI Paste, and compare it to actual remineralization products already established.
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Qian F, Szymanski A, Gao J. Fabrication and characterization of controlled release poly(D,L-lactide-co-glycolide) millirods. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2001; 55:512-22. [PMID: 11288079 DOI: 10.1002/1097-4636(20010615)55:4<512::aid-jbm1044>3.0.co;2-n] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A compression-heat molding procedure was developed to fabricate poly(D,L-lactide-co-glycolide) (PLGA) controlled release drug delivery devices for the local treatment of tumors. The drug delivery devices were designed in the shape of a cylindrical millirod (1.6-mm diameter, 10-mm length), which allows them to be implanted by a modified 14-gauge tissue biopsy needle into tumor tissues via image-guided interventional procedures. In this study, the prototype trypan blue-containing PLGA millirods were fabricated under a compression pressure of 4.6 x 10(6) Pa and different fabrication temperatures for 2 h. The scanning electron microscopy results showed complete polymer annealing for millirods fabricated at 80 and 90 degrees C, while the cross sections of the 60 and 70 degrees C millirods showed incompletely annealed PLGA microspheres and trypan blue powders. The density, flexural modulus, and release properties of the PLGA millirods were also characterized and compared. The average values of the density and flexural modulus of the millirods increased with an increase in fabrication temperature. The flexural modulus values of most PLGA millirods were above 1 x 10(8) Pa, which provides sufficient stiffness for implantation within the tumor tissue. In addition, a Delta c(p) method was developed to determine the loading density of trypan blue in the PLGA millirods by differential scanning calorimetry. Results from the Delta c(p) measurement showed that trypan blue was homogeneously distributed in the millirod. Release studies in phosphate-buffered saline showed that the release rate decreased for the millirods fabricated at higher temperatures. The times for the release of 50% trypan blue were 5, 25, 25, and 25 h for millirods fabricated at 60, 70, 80, and 90 degrees C, respectively. Millirods fabricated at 90 degrees C had the most reproducible release profiles. The results from this study established compression--heat molding as an effective method to fabricate controlled release PLGA millirods with sufficient mechanical strength and reproducible release profiles for local cancer therapy.
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